Inter-operability of terms
568
Irrespective of the effect of "dangerous goods" vs "hazardous materials" on a person's health, the accepted terms for relay to ATC or upon a request by them to state carriage of, is either "DANGEROUS GOODS" or "HAZMAT". If ATC cannot figure that out, I am certain they will ask. Generally, associated with the DANGEROUS GOODS/HAZMAT notification, is information such as POB (or SOB), and fuel on board (pounds, kilos, tonnes - whatever the gauges are calibrated in).
Cheers